Arrangement for coupling of a driver to a coupling site of the ossicular chain

ABSTRACT

A mechanical coupling for an output-side driver of an active or passive implantable hearing system. The driver is adapted to vibrate a preselected coupling site on an ossicular chain via a first coupling which has a coupling rod which can be caused to vibrate mechanically by the driver and a coupling element which can be connected to the preselected coupling site. The coupling rod and the coupling element are interconnected by at least one coupling. A first coupling half of the coupling has an approximately spherical outside contour which can be accommodated in the inside contour of a second coupling half, i.e. a contour which is at least partially complementary to the outside contour. The is adapted to reversibly swivel and/or turn against friction forces, but is essentially rigid under the dynamic forces which occur in the implanted state.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an implantable arrangement for mechanicalcoupling of an output-side driver member of an active or passive hearingsystem, the driver member being adapted to be excited to mechanicalvibrations, to a preselected coupling site on the ossicular chain, thefootplate of the stapes or a membrane which closes the round window oran artificial window in the cochlea, in the vestibulum or in thelabyrinth (equilibrium organ), via a coupling arrangement which has acoupling rod which can be excited to mechanical vibrations by the drivermember, and a coupling element which can be connected to saidpreselected coupling site, the coupling rod and the coupling elementbeing interconnected via at least one coupling and at least a section ofthe coupling element which in the implanted state contacts the couplingsite being designed for vibratory input to the coupling site.

2. Description of Related Art

Partially implantable or fully implantable active hearing systems fordirect mechanical stimulation are known. In these hearing systems theacoustic signal is converted into an electrical signal by a converter(microphone) and is amplified in an electronic signal processing unit;this amplified electrical signal is supplied to an implantedelectromechanical converter the output-side mechanical vibrations ofwhich are supplied directly, i.e. with direct mechanical contact, to themiddle ear or inner ear. This applies regardless of whether purelabyrinthine deafness with a completely intact middle ear or combineddeafness (middle ear and inner ear damaged) is to be rehabilitated.Therefore, implantable electromechanical converters and processes fordirect coupling of the mechanical converter vibrations to the intactmiddle ear or to the inner ear for rehabilitation of pure labyrinthinedeafness and also to the remaining ossicles of the middle ear in anartificially or pathologically altered middle ear for treatment ofconductive deafness and their combinations have been described in themore recent scientific and patent literature.

Basically all physical conversion principles can be used aselectromechanical converter processes, such electromagnetic,electrodynamic, magnetostrictive, dielectric, and piezoelectric. Inrecent years various research groups have focused essentially on two ofthese processes: electromagnetic and piezoelectric. An outline of theseconverter versions can be found in Zenner and Leysieffer (HNO 1997, Vol.45, pp. 749 -774).

In the piezoelectric process, mechanically direct coupling of theoutput-side converter vibrations to the middle ear ossicle or directlyto the oval window is necessary. In the electromagnetic principle, theforce coupling, on the one hand, can take place via an air gap(“contactless”), i.e. only a permanent magnet is placed by permanentfixation in direct mechanical contact with a middle ear ossicle. On theother hand, it is possible to dispose the entire converter within ahousing (the coil and the magnet being coupled with the smallestpossible air gap) and to transfer the output-side vibrations via amechanically stiff coupling element with direct contact to the middleear ossicle (Leysieffer et al., HNO 1997, Vol. 45., pp. 792-800).

The patent literature contains some of the aforementioned versions ofboth electromagnetic and also piezoelectric hearing aid converters: U.S.Pat. No. 5,707,338 (Adams et al.), WO 98/06235 (Adams et al.), WO98/06238 (Adams et al.), WO 98/06236 (Kroll et al.), WO 98/06237 (Busheket al.), U.S. Pat. No. 5,554,096 (Ball), U.S. Pat. No. 3,712,962(Epley), U.S. Pat. No. 3,870,832 (Fredrickson), U.S. Pat. No. 5,277,694(Leysieffer et al.), published European Patent Application Nos. EP-A-0984 663 and EP-A-0 984 665 (corresponding to commonly owned U.S. PatentApplication Nos. 09/275,872 and 09/311,563, respectively) (Leysieffer),U.S. Pat. No. 5,015,224 (Maniglia), U.S. Pat. No. 3,882,285 (Nunley),and U.S. Pat. No. 4,850,962 (Schaefer).

The partially implantable piezoelectric hearing system of the Japanesegroup of Suzuki and Yanigahara presupposes for implantation of theconverter the absence of the middle ear ossicles and an empty tympaniccavity in order to be able to couple the piezoelement to the stapes(Yanigahara et al.: Efficacy of the partially implantable middle earimplant in middle and inner ear disorders, Adv. Audiol., Vol. 4, KargerBasel (1988), pp. 149-159; Suzuki et al.: Implantation of partiallyimplantable middle ear implant and the indication, Adv. Audiol., Vol. 4,Karger Basel (1988), pp. 160166). Similarly, in the process of animplantable hearing system for those suffering from labyrinthinedeafness in accordance with U.S. Pat. No. 4,850,962 (Schaefer),basically, the incus is removed in order to be able to couple apiezoelectric converter element to the stapes. This also appliesespecially to other developments which are based on the Schaefertechnology and which are documented in the aforementioned patents (U.S.Pat. No. 5,707,338, WO 98/06235, WO 98/06238, WO 98/06236, and WO98/06237).

Conversely, the electromagnetic converter of BALL (“Floating MassTransducer FMT”, U.S. Pat. No. 5,624,376, and U.S. Pat. No. 5,554,096)is fixed with titanium clips directly to the long process of the incuswhen the middle ear is intact. The electromagnetic converter of thepartially implantable system of FREDRICKSON (Fredrickson et al.: Ongoinginvestigations into an implantable electromagnetic hearing aid formoderate to severe sensorineural hearing loss, Otolaryngologic Clinicsof North America, Vol. 28/1 (1995), pp. 107-121) is mechanically coupleddirectly to the body of the incus when the ossicular chain of the middleear is likewise intact. The same applies to the piezoelectric andelectromagnetic converters of LEYSIEFFER (Leysieffer et al.: Animplantable piezoelectric hearing aid converter for patients withlabyrinthine deafness, HNO 1997/45, pp. 792-800; U.S. Pat. No.5,277,694, U.S. Patent Application Nos. 09/275,872 and 09/311,563(Leysieffer)). Also, in the electromagnetic converter system of MANIGLIA(Maniglia et al: Contactless semi-implantable electromagnetic middle eardevice for the treatment of sensorineural hearing loss, OtolaryngologicClinics of North America, Vol. 28/1 (1995), pp. 121-141), when theossicular chain, is intact, a permanent magnet is permanently fixedmechanically to the ossicular chain but is, however, mechanically drivenvia an air gap coupling by a coil.

In the described converter and coupling versions, basically, twoimplantation principles can be distinguished:

a) On the one hand, the electromechanical converter with its activeconverter element is located itself in the middle ear region in thetympanic cavity and the converter is directly connected there to anossicle or the inner ear (U.S. Patent No. 4,850,962, U.S. Pat. No.5,015,225, U.S. Pat. No. 5,707,338, WO 98/06235, WO 98/06238, WO98/06236, WO 98/06237, U.S. Pat. No. 5,624,376, and U.S. Patent No.5,554,096).

b) On the other hand, the electromagnetic converter with its activeconverter element is located outside of the middle ear region in anartificially formed mastoid cavity. The output-side mechanicalvibrations are then transmitted to the middle or inner ear by means ofmechanically passive coupling elements via suitable surgical accesses(the natural aditus ad antrum, opening of the chorda-facialis angle orvia an artificial hole from the mastoid) (Fredrickson et al.: Ongoinginvestigations into an implantable electromagnetic hearing aid formoderate to severe sensorineural hearing loss, Otolaryngologic Clinicsof North America, Vol. 28/1 (1995), pp. 107-121; U.S. Pat. No.5,277,694; U.S. patent application Ser. Nos. 09/275,872 and 09/311,563(Leysieffer)).

In a)-type versions, the converter can be made as a so-called “floatingmass”converter, i.e. the converter element does not require any“reaction”,via secure screwing to the skull bone, rather it vibratesbased on the laws of mass inertia with its converter housing andtransmits these vibrations directly to a middle ear ossicle (U.S. Pat.No. 5,624,376, U.S. Pat. No. 5,554,096, U.S. Pat. No. 5,707,338, and WO98/06236). On the one hand, this means that an implantable fixationsystem on the cranial vault can be advantageously omitted, and, on theother hand, this version disadvantageously means that bulky artificialelements must be placed in the tympanic cavity, and their long-termstability and biostability are currently not known or guaranteed,especially in the case of temporary pathological changes of the middleear (for example, otitis media). Another major disadvantage is that theconverter together with its electrical supply line has to be transferredfrom the mastoid into the middle ear and must be fixed there usingsuitable surgical tools; this requires expanded access through thechorda facialis angle and, thus, entails a latent hazard to the facialnerve which is located in the immediate vicinity.

In the b)-type converter versions, the converter housing with theimplantable positioning and fixation systems is attached to the cranialvault (advantageous embodiment U.S. Pat. No. 5,788,711). Both in thepartially implantable system of FREDRICKSON (Ongoing investigations intoan implantable electromagnetic hearing aid for moderate to severesensorineural hearing loss, Otolaryngologic Clinics of North America,Vol. 28/1 (1995), pp. 107-121), as well as in the fully implantablehearing system of LEYSIEFFER and ZENNER (HNO 1998, vol. 46, pp. 853-863and 844-852), when the vibrating driver member is coupled to the body ofthe incus, it is assumed, for permanent and mechanically securevibration transmission, that the tip of the coupling rod, which isplaced in the laser-induced depression of the middle ear ossicle,undergoes osseointegration over the long term, i.e. the coupling rodcoalesces solidly with the ossicle, and thus, ensures reliabletransmission of dynamic compressive and tensile forces. This long-termeffect, however, is currently not yet scientifically proven or certain.Furthermore, in this type of coupling, in case of a technical converterdefect, there is the disadvantage that decoupling from the ossicle toremove the converter can only be done with mechanically based surgicalmethods; w this can mean considerable hazard to the middle ear andespecially the inner ear.

The major advantage of these converter embodiments as per b) however, isthat the middle ear remains largely free and coupling access to themiddle ear can take place without major possible hazard to the facialnerve. One preferable surgical process for this purpose is described inU.S. Pat. No. 6,077,215. Basic advantageous forms of passive couplingelements for transmission of the output-side converter vibrations fromthe mastoid to the middle ear or inner ear are described in U.S. Pat.No. 5,277,694; U.S. Pat. No. 5,941,814; and in HNO 1998 Vol. 46, pp.27-37—Lehner et al.: “Cold-flowing elements for coupling of animplantable hearing aid converter to the auditory ossicle or perilymph”.The coupling elements are especially made of gold, preferably,soft-annealed fme gold, in the form of a C-band for the long process ofthe incus, a band loop for the long process of the incus and a tiny bellfor the head of the stapes, and these coupling elements can be coupledusing instruments which are standard in ear surgery, and if necessary,they can also be detached again.

Commonly owned U.S. Patent Application No. 09/626,745 (filed on Jul. 26,2000 and entitled “Arrangement for Mechanical Coupling of a Driver to aCoupling Site of the Ossicular Chain”) describes an implantablearrangement for mechanical coupling of an output-side driver member ofan active or passive hearing system, the driver member being adapted tobe excited to mechanical vibrations to a preselected coupling site onthe ossicular chain, the footplate of the stapes or a membrane whichcloses the round window or an artificial window in the cochlea, in thevestibulum or in the labyrinth (equilibrium organ), via a couplingarrangement which has a coupling element which can be connected to thepreselected coupling site. An attenuator element with entropy-elasticproperties which, in the implanted state, contacts the coupling site,causes a coupling with low characteristic acoustic impedance and areduction of the risk of damage to natural structures in the area of thecoupling site during and after implantation.

WO 99/08475 discloses an active hearing system in which a capacitivesensor converts vibrations of the malleus into an electrical signalwhich after passing through an electronic circuit is supplied to astimulator, which for its part, mechanically or electrically stimulatesthe inner ear. The capacitive sensor includes a first electrode, whichis pivotally coupled to the malleus via a ball joint coupling, and asecond electrode, which is either rigidly fixed to the mastoid or islikewise pivotally coupled to the mastoid via a ball joint coupling. Theball joint coupling is designed such that the two electrodes can freelyalign themselves with respect to one another even if the vibrationdirection of the malleus changes for example as a function of frequency.

An arrangement is described in U.S. Pat. No. 5,941,814 in which thefirst coupling half is essentially rod-shaped and the second couplinghalf is made roughly sleeve-shaped, and by pushing and/or turning thetwo coupling halves, the relative location of the coupling rod andcoupling element can be adjusted in situ at the implantation site. Thetwo components are fixed reliably with long term stability in the setrelative position by applying a crimping force, using a crimping tool,to the sleeve-shaped second coupling half, by which the latter isplastically cold-formed, whereas the rod-shaped first coupling half isnot subjected to plastic cold-forming under the action of a crimpingforce.

In addition to the described active hearing systems, passive hearingsystems are also known in the form of prostheses as total replacement(T.O.R.P.=total ossicular replacement prosthesis) or as partialreplacement (P.O.R.P.=partial ossicular replacement prosthesis) for theossicular chain (D.I. Bojrab et al. “Ossiculoplasty with compositeprostheses”,in Otolaryngologic Clinics of North America, Vol. 27, No. 4,1994, pp. 759-776). In these passive systems the eardrum itself or anarea of the still intact “remainder”,of the ossicular chain facing theeardrum forms the output-side driver member. Thus, U.S. Pat. No.5,370,689 discloses as a stapes replacement a passive middle earprosthesis which comprises an elongated rod section one end of which isconnected to the footplate of the stapes. An eyelet is provided at theother end of the rod section and is pushed over the free end of the longprocess of the incus. The motion of the stapes replacement which isdriven by the long process of the incus is modified by a hitching memberwhich is engaged by the stapedial tendon. For this reason the hitchingmember is slipped onto the rod section, the fit between the rod sectionand the inside surface of the hitching member being chosen such that thetwo parts can be moved relative to one another during implantation,whereas unwanted axial or rotational motion of the hitching member afterimplantation is precluded.

SUMMARY OF THE INVENTION

It is an object of this invention to provide for an arrangement whichmakes it possible to adjust the relative position of the two couplinghalves of the coupling at the implantation site in situ as sensitivelyas possible in many degrees of freedom, the set relative position afterimplantation being reliably preserved in a simple manner with long termstability.

In conformity with the invention the arrangement includes a firstcoupling half of the coupling that has an outside contour with at leastapproximately the shape of a spherical cap which is adapted to bereceived in an inside contour of a second coupling half, with thisinside contour being at least partially complementary to the saidoutside contour, wherein the coupling is adapted to be reversiblyswiveled and/or turned against friction forces, but is essentially rigidwith respect to dynamic forces which occur in the implanted state.

This arrangement provides an especially simple and nevertheless reliablemanner that allows for moving the two coupling halves duringimplantation into a desired relative position. After implantation themechanical vibrations which are induced in the first or second couplinghalf and which originate from the driver part are transmittedessentially rigidly to the other coupling half without the need for anyadditional operational step for this purpose. Proceeding from thestipulated known dynamic forces which must be transmitted in theimplanted state by the coupling and from the higher forces which aretypically applied by the surgeon in the course of implantation, theparameters which significantly influence the properties of the pair ofthe two coupling halves, such as the material, surface roughness(microgeometry) and fit (macrogeometry) are chosen such that especiallythe stick-slip effect and forces of friction between the coupling halvesallow an easy, statically reversible adjustment of the coupling duringimplantation under the influence of the forces applied by the surgeon,whereas the coupling is rigid with respect to the dynamic forces to betransmitted in the implanted state.

The handling of the arrangement can be greatly simplified if thecoupling is designed for reversible coupling and decoupling.

The second coupling half of the coupling can have at least two springarms by which the first coupling half can be at least partiallyencompassed. The spring arms which can be connected by a materialconnection, for example soldering, brazing, welding, or the like, orwhich also can be made in one piece, can preferably contact the firstcoupling half with inwardly directed spring bias.

Furthermore, the second coupling half of the coupling can also haveapproximately a bell shape and can include especially several slotswhich extend essentially perpendicular to the peripheral direction andwhich extend to a face of the second coupling half facing the firstcoupling half. In this way, the first coupling half can be reliably heldin the second coupling half At the same time, sufficient flexibility ofthe second coupling half for reversible coupling and decoupling isprovided for.

Another advantageous embodiment of the invention has a second couplingwhich can be reversibly moved linearly and/or rotationally againstfriction forces, but is essentially rigid under the dynamic forces whichoccur in the implanted state. The first coupling half has an outsidecontour with an at least approximately cylindrical, preferablycircularly cylindrical, shape which can be accommodated in an insidecontour of the second coupling half, a contour which is at leastpartially complementary to the outside contour. The second coupling ispreferably designed for reversible coupling and decoupling and can bepositioned both between the coupling in which the first coupling halfhas approximately the shape of a spherical cap (first coupling) and thedriver member and also between the first coupling and the coupling site.It is preferred that in the implanted state transmission of dynamicforces between the two coupling halves of the second coupling takesplace essentially in the direction of the longitudinal axis of the firstcoupling half

An especially simple structure arises when the second coupling half ofthe second coupling is made as a sleeve. The sleeve can have at leastone slot which runs essentially in its longitudinal direction and whichextends at least over a part of the sleeve length. Furthermore, toincrease the flexibility, at least one slot can extend to a face of thesleeve facing the first coupling half.

If the slot extends over the entire length of the sleeve, the wall inthe region of the two edges of the slot can be formed to point outwardlyand the wall can defme an insertion section into which the firstcoupling half can be inserted essentially perpendicular to itslongitudinal axis.

At least one slot can end at least on one side in a relief opening whichincreases the elasticity of the second coupling half and its safetyagainst damage, and which has a boundary line which connects the twosides of the slot, the relief opening transversely to the slot directionhaving a dimension which is greater than that of the slot.

The boundary line of at least one relief opening can connect the sidesof the slot in an arc, especially essentially in a circular arc, or canbe made in the form of a transversal slot which runs essentiallyperpendicular to the slot.

In another embodiment of the invention, at least one section of the wallof the sleeve of the second coupling is adapted to contact the firstcoupling half in an inwardly spring-biased manner. Furthermore, therecan be at least two slots, and at least one section of a wall of thesleeve located between two adjacent slots is adapted to contact thefirst coupling half in an inwardly spring-biased manner. In doing so, itcan be provided that at least two adjacent slots are connected to oneanother on the end side thereof, especially essentially in a U-shapemanner, so that a spring tongue is formed.

To facilitate the coupling and decoupling process, the outside contourof the first coupling half of the second coupling in the area of its endfacing the second coupling half can be provided with an insertion areawhich tapers in the direction towards the end.

For this purpose the inside contour of the second coupling half of atleast one coupling in the area of its end facing the first coupling halfcan also be provided with an insertion area which widens in thedirection towards the end. This applies both to the first and also thesecond coupling.

Moreover, at least a first and/or a second coupling half of at least onecoupling can be advantageously connected integrally to the associatedcoupling element or the associated coupling rod.

The arrangement of the invention can be part of an active, partiallyimplantable or fully implantable hearing system in which the output-sidedriver member is a vibratory member, especially a vibratory membrane, ofan electromechanical hearing aid converter. The arrangement of theinvention can however also be part of a passive hearing system,especially a partial or full middle ear prosthesis in which in theimplanted state the eardrum is used as the output-side driver member.

These and further objects, features and advantages of the presentinvention will become apparent from the following description when takenin connection with the accompanying drawings which, for purposes ofillustration only, show several embodiments in accordance with thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged view of an implanted hearing aid converter and acoupling arrangement with a coupling rod driven by the hearing aidconverter, and a coupling element which is connected, on the one hand,via a coupling to the coupling rod, and on the other, is coupled to theossicular chain;

FIG. 2 shows, on a still larger scale, a perspective view of the hearingaid converter as shown in FIG. 1 which is coupled via a modifiedcoupling arrangement to the body of the incus;

FIG. 3 is an enlarged perspective view of the area of FIG. 2 which isprovided with a circle III;

FIGS. 4 and 5 are views of an embodiment of the invention in which thecoupling between the coupling rod and the coupling element is made as aball joint coupling;

FIG. 6 is a perspective view of a modified coupling element with analtered ball joint coupling;

FIGS. 7 to 11 are perspective views of modified coupling elements withtwo couplings, the first coupling being made as a ball joint couplingand the second coupling being made as a plug coupling;

FIGS. 12 to 15 are perspective views of additional modified plugcouplings;

FIGS. 16 and 17 are cross-sectional views of the plug coupling of FIG.15; and

FIG. 18 is a perspective view of a passive middle ear prosthesis with aball joint coupling.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows part of a human skull bone 1 with the auditory canal 2, themiddle ear space (tympanic cavity) 4 which is separated therefrom by theeardrum 3, and the ossicular chain 5 which is located in the tympaniccavity. The ossicular chain 5 includes the malleus 6, the incus 7 withthe long process 8 of the incus, and the stapes 9 with the footplate 10of the stapes. In an artificial mastoid cavity 12, an electromechanicalhearing aid converter 13 is fixed by means of a positioning and fixingsystem 14. The hearing aid converter 13 can be built, for example, as apiezoconverter for vibratory stimulation of the ossicular chainespecially in the manner known from U.S. Pat. No. 5,277,694 and it is acomponent of an at least partially implantable and preferably fullyimplantable hearing aid, for example a hearing aid of the type knownfrom HNO 1997 Vol. 45, pp. 749-774.

A vibration transmission path in the form of a biocompatible,mechanically passive coupling arrangement 17 is provided formechanically coupling an outputside driver member 15 of the hearing aidconverter 13 to a preselected coupling site 16 on the ossicular chain 5,for example to the “smooth”, body of the incus 7, from the mastoid side,wherein the output-side driver member 15 is shown only schematically inFIG. 1, can be excited to mechanical vibrations, and preferably may be avibratory membrane of this converter. The coupling arrangement 17 isconnected to the actively vibrational output-side driver member 15 and,in the implanted state, it contacts the coupling site 16 with thecoupling end which is remote from the hearing aid converter 13. When anelectrical voltage is applied to the hearing aid converter 13, thecoupling arrangement 17 is caused by means of the output-side drivermember 15 to execute vibratory oscillations in the axial direction ofthe coupling arrangement. As a result, the electrically converted audiosignals which are picked up by an input-side converter (microphone) (notshown), after electronic amplification in an electronic module of theactive hearing system, lead directly to mechanical deflections of thecoupling arrangement 17. These deflections correspond to the acousticinformation. The deflections of the coupling arrangement 17 are relayedto the ossicular chain 5 of the middle ear or to the stapes 9, thefootplate 10 of the stapes or a membrane which is not shown and whichcloses the oval or round window or an artificial window in the cochlea,in the vestibulum or in the labyrinth (equilibrium organ). Thedeflections of the coupling arrangement therefore cause an audiologicalamplification effect for a corresponding design of the preprocessingelectronic system.

The coupling arrangement 17 has a coupling rod 19 which is mechanicallyjoined securely to the output-side driver member 15 and which, in theembodiment shown, has essentially over its entire length the shape of astraight cylinder. The coupling rod 19 extends in the implanted statefrom the mastoid cavity 12 into the tympanic cavity 4 preferably througha natural, if necessary artificially widened, bone opening (aditus adantrum) 21 which is located in the rear wall 20 of the auditory canal.The coupling arrangement 17 furthermore includes a coupling element 22which is connected via a coupling 23 to the end of the coupling rod 19remote from the hearing aid converter 13 and is coupled to the couplingsite 16 via a coupling end.

The schematically shown coupling 23 comprises two coupling halves, ofwhich the first coupling half has an outside contour with at leastapproximately the shape of a spherical cap which can be accommodated inthe inside contour of a second coupling half, a contour which is atleast partially complementary to the outside contour. The first couplinghalf is formed, preferably integrally, on the free end of the couplingrod 19. The coupling 23 is made such that it can be reversibly swiveledand turned against friction forces by the surgeon during implantationbut is essentially rigid for the dynamic forces which occur in theimplanted state. Thus, sensitive matching of the relative position ofthe coupling rod 19 and the coupling element 22 to the circumstances ofthe implantation site in situ is possible, the relative position onceset after implantation no longer being changed by the dynamic forceswhich then occur.

FIGS. 2 and 3 show a coupling arrangement with a coupling 34 which ismade as a ball joint coupling and with a first coupling half 36 whichhas a ball head 80 which can be inserted into a second coupling half 38in the form of a ball receiver 79. The ball receiver 79 has anapproximately bell-like shape with several slots 26 which extend from aface 42 towards the first coupling half 36 essentially perpendicular tothe peripheral direction of the ball receiver 79. In this way springarms 28 are formed which can spring reversibly to the outside during thecoupling and decoupling process, an insertion area 30 which widens tothe outside in the direction towards the face 42 facilitating thecoupling of the ball head 80 to the ball receiver 79.

While the ball head 80 is made in one piece with the coupling rod 19,the ball receiver 79 merges via a connection piece 25 into a couplingrod-side end 67 of a coupling element 68. The coupling element 68 ismade as a twin-arm lever with two arms 76 and 77 and is supported in themiddle area thereof on the short process 69 of the incus. If thecoupling rod-side end 67 of the arm 76 is forced to move according tothe double arrow 71 by means of the coupling rod 19, the couplingelement 68 swivels around a pivot 72 which is defmed by the shortprocess 69 of the incus. In this way, a coupling end 73 of the couplingelement 68 which is located on the arm 77 and which engages the longprocess 8 of the incus via a spring clamp 74 or the like is moved in thedirection of a double arrow 75. By correspondingly dimensioning therelative lengths of the arms 76 and 77 of the coupling element 68 adesired lever ratio can be set. The coupling 34 can not only be turnedand swiveled in situ, it can also be coupled and decoupled at theimplantation site, whereby the manageability of the device is greatlyimproved. After implantation, the set relative position of the couplingrod 19 and of the coupling element 68 is no longer changed by thedynamic forces which occur.

In a modified embodiment, as shown in FIGS. 4 and 5, there is a coupling82 in the form of a ball joint coupling with a first coupling half whichcomprises a ball 103 which on the end of the coupling rod 19′ facingaway from the hearing aid converter 13 is joined integrally with therod. The coupling element 83 can be an elastic clamp consisting of twospring arms 126 and 127, which are joined, preferably welded, to oneanother at 125. The spring arms, 126 and 127, form on the one hand asecond coupling half in the form of a ball receiver 121 for the ball 103of the coupling rod 19′ and on the other hand a receiving opening 86with a spreadable passage 87 for the target ossicle 8. To facilitate thecoupling process between the two coupling halves of the coupling 82, theball receiver 121 is provided with an insertion area 84 which widens inthe direction to a face 90, the passage 87 for the target ossicle 8being placed in a coupling end 100 of the coupling element 83 with aface 122 which is located essentially perpendicular to the face 90.

The coupling element 83 can be inserted by means of the coupling rod 19′through the opening 21 in the rear wall 20 of the auditory canal intothe middle ear space 4 and can be positioned such that the spreadablepassage 87 is aligned with the target ossicle, for example the longprocess 8 of the incus according to FIG. 4. Then the coupling element 83is pressed down, and thus, swiveled in the direction of arrow 133 inFIG. 5 with reference to the coupling rod 19′ until the target ossicle 8lies in the receiving opening 86, with the passage 87 being widened. Inthis way reliable coupling to the target ossicle is achieved. In theimplanted state, the coupling rod 19′ executes vibrations essentially inthe direction of the double arrow 88, the coupling 82 rigidlytransmitting the vibrations.

A coupling element 117 which is shown in FIG. 6 comprises two undulatingspring arms 119 which are welded together at 118 and which, on one sideof the connection point 118, form a ball receiver 123 for the ball 103of the coupling rod 19′ and, on the other side of this connection point,form the spreadable passage 87 and the receiving opening 86 for thetarget ossicle. The coupling element 117 can be turned and swiveledrelative to the coupling rod 19′ according to the group of arrows 107and it differs from the coupling element 83 as shown in FIGS. 4 and 5essentially in that the ball receiver 123 as the second coupling half ofa coupling 114 has no section corresponding to the insertion area 84 andaccordingly cannot be reversibly coupled and decoupled. Furthermore, aface 128 which defmes the passage 87 for the target ossicle, in contrastto the embodiment of FIGS. 4 and 5, is approximately parallel to theface 130 which delimits the second coupling half comprising the ballreceiver 123. The coupling 114 also rigidly transmits the dynamic forceswhich occur in the implanted state.

In a modified embodiment of the arrangement of the invention as shown inFIGS. 7 and 8, a first and a second coupling are series connected, thecoupling 114 of FIG. 6 being used as the first coupling. Instead of withthe coupling rod 19′, the ball 103 is, however, connected to a stem 142of an intermediate element 164, which stem 142 is fixed via a wideningsection 158 to a sleeve 150 of a second coupling half 144 of the secondcoupling 146. A first coupling half 148 of the coupling 146 is formed athe free end of a coupling rod 19″,the second end of which connected tothe hearing aid converter and being caused thereby to vibrate. In orderto be able to insert the free end of the coupling rod 19″,facing awayfrom the hearing aid converter 13 more easily into the sleeve 150 of thesecond coupling 146 which is made as a plug coupling, an insertion area162 is provided at the free end of the coupling rod 19″, which insertionarea tapers towards the free end of the coupling rod 19″ . The sleeve150 in its wall 160 has several slots 152 which run essentially in thelongitudinal direction of the sleeve 150 and which are approximatelyuniformly distributed around the circumference, and they end in front ofthe face 156 at the free end of the sleeve 150. A bridge 154 is formedbetween each pair of adjacent slots 152 which bridge is inwardly biasedand contacts the first coupling half 148 with a stipulated contact forcewhen the first coupling half 148 is inserted into the sleeve 150.

The series connection of two couplings in particular has the advantagethat during implantation the arrangement at first can be divided intotwo modules by detaching the coupling 146, which modules can be handledseparately and which again are connected to each other after thecoupling element 117 has been coupled, by means of its receiving opening86, to the target ossicle. The coupling 146 can be reversibly coupledand decoupled by the surgeon and in doing so can be shifted in situ inthe longitudinal direction of the sleeve 150 and turned around thelongitudinal axis of the sleeve 150, the design of the coupling 146being such that the relative rotational and translatory position of thetwo coupling halves 144 and 148 which is adjusted by the surgeon remainsstably preserved under the dynamic forces which occur in the implantedstate, at least as long as a stipulated minimum insertion depth of thefirst coupling half 148 into the second coupling half 144 is maintained.Also, the other ball joint couplings and plug couplings described belowcan be moved in a statically reversible manner against friction forcesduring implantation, but rigidly transmit the lower dynamic forces whichoccur in the implanted state. FIGS. 9 and 10 show another embodiment ofan arrangement in which, likewise, two series-connected couplings areused, a coupling 171 made as a plug coupling and a coupling 173 made inthe form of a ball joint coupling. An intermediate element 166 differsfrom the intermediate element 164 of FIGS. 7 and 8 essentially only inthat the second coupling half of the coupling 171 comprises a modifiedsleeve 168 which is provided with a single slot 170 which, proceedingfrom one face 204 on the free end of the sleeve 168, extends in thelongitudinal direction of the sleeve and terminates in an essentiallyround relief opening 172 which joins the two sides 174 of the slot. Theplug coupling 171 is designed such that the first coupling half 148which is provided on the coupling rod 19″,is always inserted into areceiver 192 of the sleeve 168 until the free end of the first couplinghalf 148 comes to rest against a depth stop 206 within the sleeve 168.Optical inspection of the plug process is possible through the slot 170.

A coupling element 176 is made in one piece and comprises, as the secondcoupling half of the coupling 173, a ball receiver 184 which is formedby two opposite spring arms 186 and 188 which both extend to acoupling-side face 185 of the coupling element 176. To increase theflexibility of the spring arm 188 the latter is extended in a U-shape inthe direction towards a receiving opening 182 for the target ossicle. Aleg 193 opposite a spring arm 189 is connected via a crosspiece 191 tothe spring arm 186, with a crosspiece 187, which is provided between theleg 193 and the spring arm 189, being designed such that its outsidesurface facing away from the ball receiver 184 together with an innersurface of a spring clip 180 forms the receiving opening 182. The springclip 180 is formed on the side of the crosspiece 191 opposite the springarm 186 to the crosspiece and at first runs, as a thin-walled extensionof the spring clip 186, substantially parallel to the leg 193 and thenmerges into an arc-shaped segment 181. The free end of the segment 181ends essentially at the same height as a side surface 189 of the springarm 188 so that the target ossicle is inserted substantiallyperpendicular with reference to the side surface 189 into the receivingopening 182 which is provided on the coupling end 178 of the couplingelement 176. The side surface 189 is aligned substantially perpendicularwith reference to a plane containing the face 185. An opening 190 ismade in each of the spring arms 186 and 188 such that the two openingshave a common longitudinal axis which extends through the center of theball 103. In this way, the faces of the openings 190 facing the ball103, each form a defined contact surface for the ball 103, which contactsurfaces can be made in the manner of a ball socket. Preferably, theentire coupling element 176 is made of titanium or a titanium alloy.

FIG. 11 shows an arrangement in which the ball joint coupling is thecoupling 34 as shown in FIGS. 2 and 3 and the plug coupling is thecoupling 171 of FIGS. 9 and 10, the second coupling half 38 of thecoupling 34 being connected to a stem 194 the free end of which definesthe first coupling half of the coupling 171. In contrast to theembodiment shown in FIGS. 9 and 10, the stem 142, which is connected tothe sleeve 168, however, does not terminate in the ball 103, but mergesinto a coupling end 202 for the target ossicle. The coupling end 202comprises a band loop 198 which forms a receiving opening 200 for thetarget ossicle and which can be placed for example around the longprocess 8 of the incus. The sleeve 168 and the stem 142 are made in onepiece and the material is preferably titanium or a titanium alloy,whereas the band loop 198 is made especially of gold or a gold alloy.

The plug coupling which is shown in FIG. 12 differs from the coupling171 as shown in FIGS. 9 and 10 mainly in that a slot 210, which is madein the sleeve 208 on its end facing away from a face 212, does not endin a round relief opening corresponding to the relief opening 172 of thesleeve 168, but ends in a transverse slot 214 which is made essentiallyperpendicular to the slot 210.

Other modified plug couplings are shown in FIGS. 13 to 17. Thus, in aplug coupling as shown in FIG. 13 a first coupling half 217, which isformed at the free end of a coupling rod 19″, is inserted in thedirection of arrow 226, essentially perpendicular to the longitudinalaxis of a second coupling half which is made as a sleeve 216. For thispurpose the sleeve 216 is provided with a slot which extends over thefull length of the sleeve, wherein a wall 228 of the sleeve 216, in thearea of both sides 222 of the slot, is formed to point outwardly so thatan insertion area 224 results. When the first coupling half 217 iscoupled to sleeve 216, an outer wall of the first coupling half 217cooperates with the insertion area 224 and facilitates spring wideningof the sleeve 216. The sleeve 216 is connected, especially welded,brazed or soldered, on its outer side which is substantiallydiametrically opposite the slot, to a stem 218 of the couplingarrangement via connection points 220.

The plug coupling which is shown in FIG. 14 also comprises as the secondcoupling half a sleeve 230 with a continuous slot, but in contrast tothe sleeve 216 as shown in FIG. 13, an outwardly widening insertion area232 is provided at a face 236 of a free end of the sleeve 230, and thewall of the sleeve 230 otherwise has an approximately circularcylindrical shape. The coupling of the first coupling half 217 to thesleeve 230 takes place, essentially, in the longitudinal direction ofthe sleeve, the insertion area 232 of the sleeve 230 interacting with aconically tapering insertion area 234 which is provided on the free endof the first coupling half 217 and which facilitates the spring wideningof the sleeve 230.

FIGS. 15 to 17 show another modified plug coupling which differs fromthe coupling 146 shown in FIGS. 7 and 8, essentially, only by theconfiguration of slots 240 in a wall 248 of the second coupling half,which is made as a sleeve 238. Like the slots 152 in the sleeve 150 asshown in FIGS. 7 and 8, the slots 240 in the sleeve 238 also run,essentially, in the longitudinal direction of the sleeve and terminatein front of a face 242 of the sleeve 238. But, overall, four slots 240are made in the wall 248 of the sleeve 238 such that each two slots 240are more closely spaced from each other and are interconnected on theirend facing away from the face 242 via an essentially U-shaped slotsegment 250. Thereby two diametrically opposite spring tongues 244 areformed which are inwardly spring-biased, wherein a free end of thetongues 244 projects in an arc shape to the inside and can be placedagainst the outside surface of the first coupling half 148 via a contactsurface 246.

FIG. 18 shows an implanted passive hearing system in which the eardrum 3is used as the output-side driver member which can be excited tomechanical vibrations. The eardrum 3 is contacted by a head 136 of aT.O.R.P. (total ossicular replacement prosthesis) 135, the head 136having a rounded surface. The head 136 is adjoined by a coupling rod139, which can be joined integrally to the head 136 and which has a freeend which is connected to the free end of a coupling element 137 via acoupling 140 which is made as a ball joint coupling. A coupling end 138of the coupling element 137 facing away from the coupling 140 is coupledto the head 141 of the stapes. The coupling 140 during implantationallows reversible static swiveling and turning of the coupling element137 and the coupling rod 139 with reference to one another, but rigidlytransfers the dynamic forces which are delivered to the coupling in theimplanted state by the eardrum 3. Preferably, the head 136, the couplingrod 139 and the coupling element 137 are made of an implantable metallicor ceramic material.

In general, all known biocompatible metals and their alloys can be usedas the materials for the coupling rod, the coupling element, thecoupling and the intermediate element which is inserted, if necessary,between the two couplings, particularly implantable titanium, especiallypure titanium with a purity >99.6%. In addition, among others, platinum,niobium, or tantalum or alloys of titanium, platinum, niobium ortantalum are suited. Optionally, the coupling rod or other of theindicated components can, however, also be made of an implantableceramic material, especially aluminum oxide. But also, long-termimplantable plastics can be provided, such as, among others,cross-linked silicones, polyurethanes, PTFE, FEP, polycarbonates and thelike, which can be optionally fiber reinforced, especially carbon fiberreinforced. However, at least a section of the coupling element, whichsection in the implanted state contacts the coupling site on theossicular chain, the is footplate of the stapes or a membrane whichcloses the round window or an artificial window in the cochlea, in thevestibulum or in the labyrinth (equilibrium organ), is designed forvibratory input to the coupling site, and thus, has only low entropyelasticity. This section of the coupling element contacting the couplingsite is made preferably of one of the indicated metallic or ceramicmaterials or is made of gold or a gold alloy.

While various embodiments in accordance with the present invention havebeen shown and described, it is understood that the invention is notlimited thereto, and is susceptible to numerous changes andmodifications as known to those skilled in the art. Therefore, thisinvention is not limited to the details shown and described herein, andincludes all such changes and modifications.

What is claimed is:
 1. A coupling system for use with an output-sidedriver of an implantable hearing system, said coupling system having afirst coupling with a coupling rod and a coupling element, said firstcoupling comprising: a first coupling half with an approximatelyspherical outside contour; and a second coupling half that is adapted toreceive said spherical outside contour of said first coupling half andhaving an inside contour that is complementary to said spherical outsidecontour of said first coupling half, wherein said coupling is adapted tobe substantially rigid with respect to dynamic forces which occur whensaid hearing system is implanted and adapted to at least one of swiveland turn against friction forces when said hearing system is being atleast one of implanted and adjusted.
 2. The coupling system of claim 1,wherein said first coupling is adapted to reversibly couple anddecouple.
 3. The coupling system of claim 1, wherein said secondcoupling half comprises at least two spring arms which are adapted to atleast partially encompass said first coupling half.
 4. The couplingsystem of claim 3, wherein said at least two spring arms are elasticallypretensioned toward the inside of said second coupling half such thatsaid spring arms are adapted to squeeze said first coupling half whensaid first coupling half is coupled with said second coupling half. 5.The coupling system of claim 1, wherein said second coupling half isapproximately bell-shaped.
 6. The coupling system of claim 5, whereinsaid second coupling half includes a plurality of slots extending from aface of said second coupling half.
 7. The coupling system of claim 1,further comprising a second coupling having: a first coupling halfhaving an approximately cylindrical outside contour; and a secondcoupling half that is adapted to receive said outside contour of saidfirst coupling half and having an inside contour that is at least partlycomplementary to said outside contour of said first coupling half. 8.The coupling system of claim 7, wherein said outside contour of saidfirst coupling half of said second coupling has a circular cylindricalshape.
 9. The coupling system of claim 7, wherein said second couplinghalf of said second coupling is a sleeve.
 10. The coupling system ofclaim 9, wherein said sleeve has at least one slot that runs axiallyalong said sleeve.
 11. The coupling system of claim 10, wherein at leastone slot extends to a face of said sleeve.
 12. The coupling system ofclaim 10, wherein a slot extends along the entire length of said sleeve.13. The coupling system of claim 10, wherein at least one slot does notextend to a face of said sleeve.
 14. The coupling system of claim 10,wherein at least one slot ends in a relief opening having a boundarythat connects two sides of said at least one slot, wherein said reliefopening has a transverse dimension that is greater than the transversewidth of said at least one slot.
 15. The coupling system of claim 14,wherein said boundary is arc-shaped.
 16. The coupling system of claim15, wherein said boundary is circular.
 17. The coupling system of claim14, wherein said relief opening extends perpendicularly with respect tosaid at least one slot.
 18. The coupling system of claim 9, wherein atleast one section of a wall of said sleeve is elastically pretensionedtoward the inside of said sleeve.
 19. The coupling system of claim 9,wherein said sleeve includes at least two adjacent slots defining a wallthat is elastically pretensioned toward the inside of said sleeve. 20.The coupling system of claim 19, wherein said at least two adjacentslots are connected at their ends by a U-shaped slot.
 21. The couplingsystem of claim 8, wherein said sleeve has an insertion area that taperstoward an end face of said sleeve.
 22. The coupling system of claim 8,wherein said second coupling is adapted to transmit dynamic forcesbetween said first and second coupling halves in an axial direction whenimplanted.
 23. The coupling system of claim
 7. wherein one of saidsecond coupling halves has an insertion area for said correspondingfirst coupling half that widens toward the end face of the secondcoupling half.
 24. The coupling system of claim 7, wherein at least oneof said first and second halves of one of said first and secondcouplings is connected integrally to a corresponding one of saidcoupling element and coupling rod.